Backfat quality of South African pigs: a meat processing perspective

[摘要] English: Fat quality of backfat from 2107 baconer pig carcasses, sampled at a major South African pig abattoir, wereevaluated to obtain an overview of the backfat quality of South African pigs. Extracted fat was used todetermine iodine and refraction index values as well as fatty acid profiles of these samples. Significantdifferences (P < 0.001) in terms of backfat quality were observed between the different classification groups.Improved fat quality was associated with increased backfat thickness and decreased lean meat content,caused by an increase in the total saturated and mono-unsaturated fatty acid contents and a decrease in thetotal unsaturated and polyunsaturated fatty acid contents as well as double bond and peroxidizabilityindexes. The Pand 0 classification groups (with backfat thickness measurements less than 17 mm) couldnot conform to the international standards proposed for backfat of good technological quality. The C, U andS groups (with backfat measurements of 23 to more than 32 mm) possessed backfat with good technologicalqualities. The R group had borderline fat quality. A high linoleic acid content, leading to a high dienoic fattyacid content, in turn influencing the total polyunsaturated fatty acid content, is the main cause of soft fat withpoor technological quality.Correlation analyses and statistical techniques were employed to acquire equations to describe therelationships between iodine value and international fat quality parameters. Sy substituting the internationalfat quality criteria into the equations it became clear that pigs had to have an iodine value of 60 to complywith most of these criteria, which was unrealistic. The French system predicts fat quality by utilizing backfatthickness and lean meat content. It was proposed, through modification of this system, that South African pigcarcasses with a backfat thickness of more than 17.8 mm and a lean meat content of less than 66.8% wouldhave the potential to deliver backfat with good technological properties in terms of iodine value. If these newcriteria were applied, the Pand 0 classification groups did not possess good quality fat. The probability ofselecting a pig with an iodine value < 70 (indicating good fat quality) from the R group would then be > 55%.In the S group, > 77% of the pigs conformed to these new criteria. Pigs with poor fat quality may escapedetection, but the risk of selecting a pig with poor fat quality from these groups is reduced. These values areapplicable to either method of carcass evaluation (HGP or Intrascape) employed in South Africa. Themethod developed in this study therefore provides the South African meat industry with a cost-effectivemethod to improve the probability of selecting pig carcasses with good fat quality.Soars had much better omega-6 to omega-3 ratios, lower slaughter weights and extractable fat contentscompared to barrows and gilts combined. A significant seasonal trend in the backfat iodine values wasobserved. Setter fat quality was detected in mid-summer than in mid-winter. This seasonal effect was solarge that improvement of winter backfat quality would cause the overall fat quality to improve. This couldpossibly be achieved by including feed ingredients rich in saturated fatty acids in the winter rations of pigsbecause fatty acid composition of the feed is reflected in the backfat of pigs.Large variation in fat quality existed between pigs within the same group originating from different suppliers.Within the P classification group, pigs with both highly acceptable and highly unacceptable iodine valueswere observed. Feeding, breeding, environmental and/or management differences between the supplierscould account for this. Fat quality influences the consumer, supplier as well as the meat technologist.

[发布机构] University of the Free State